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1

Durability and narrow pore size distribution (PSD) of carbons fabricated from Salix Viminalis wood

Łukaszewicz J.P., Zieliński K.

Chemical and Process Engineering

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2011

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Vol. 32, nr 3

195-201

EN

Microporous carbon molecular sieves of extremely narrow pore size distribution were obtained by carbonization of a novel raw material (Salix viminalis). The precursor is inexpensive and widely accessible. The pore capacity and specific surface area are upgradable by H3PO4 treatment without significant change of narrowed PSD. The dominating pore size indicates that these molecular sieves are a potential competitor to other nanoporous materials such as opened and purified carbon nanotubes.

2

Charakterystyka mikroporowatej struktury węglowych sit cząsteczkowych określona metodą sond molekularnych

Vogt E., Buczek B.

Karbo

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2005

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Nr 1

20-23

PL

Badaniom poddano węglowe sita cząsteczkowe używane oryginalnie do rozdzielania mieszanin gazowych, w procesach równowagowych względnie kinetycznych. Wykonano oznaczenia izoterm adsorpcji azotu w temperaturze ciekłego azotu (77 K). W przypadku sit kinetycznych uzyskane wartości adsorpcji były tak niskie, że na ich podstawie nie można było obliczyć wartości parametrów charakteryzujących strukturę porowatą. Dla sit równowagowych obliczono parametry struktury, w oparciu o równanie Dubinina-Raduszkiewicza oraz metodą Horvatha-Kavazoe. Średnicę i objętość mikroporów obliczano na podstawie wyników uzyskanych z pomiaru gęstości efektywnej. Użyto w trakcie pomiarów media piknometryczne (hel, metanol, czterochlorometan i dekalina), których wielkości średnic kinetycznych cząsteczek decydują o możliwości ich penetracji w głąb porów o określonych rozmiarach. Analiza otrzymanych wyników umożliwia dobór odpowiednich mediów piknometrycznych do badania gęstości efektywnej i struktury mikroporowatej kinetycznych sit cząsteczkowych.

EN

The kinetic and equilibrium carbon molecular sieves (CMS), used originally for separation of gaseous mixtures, were investigated. The adsorption N2 isotherms at 77 K, in static conditions where obtained. In the case of the kinetic CMSs the adsorption was so low that the calculation of parameters characterizing the texture was impossible. The volume of nitrogen adsorbed on the equilibrium CMSs is remarkable. From obtained results parameters characterizing micropore structure according to Dubinin-Ra-dushkevich equation and Horvath-Kawazoe method were determined. The diameter and volume of the micropores were determined by the measurement of the specific density using as displacement molecules with different sizes, e.g., helium, methanol, carbon tetra chloride, and decaline. The analysis of obtained results made possible to select of pycnometric fluids which are suitable for determine microporous structure of kinetics CMSs.

3

Dobór węglowych sit molekularnych do rozdziału wybranych mieszanin gazowych

Bałys M., Buczek B., Ziętkiewicz J.

Inżynieria i Ochrona Środowiska

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2004

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T. 7, nr 3/4

305-316

PL

Porównano produkowane przemysłowo i wytwarzane laboratoryjnie węglowe sita molekularne pod kątem możliwości ich zastosowania do wydzielania metanu z mieszanin CH4/N2 w procesach kontrolowanych przez równowagę adsorpcyjną oraz sita molekularne do wydzielania metanu z mieszanin CH4/CO2 oraz azotu z powietrza w procesach kontrolowanych przez kinetykę adsorpcji. Badania obejmowały charakterystyki adsorpcyjne, badania izoterm adsorpcji metanu i azotu przy podwyższonych ciśnieniach, badania izoterm i kinetyk adsorpcji CO2 i metanu. Przeprowadzono także testy dynamiczne w laboratoryjnej aparaturze przepływowej. Na ich podstawie wytypowano adsorbenty o największej przydatności dla otrzymywania metanu w procesach adsorpcji zmiennociśnieniowej.

EN

Selection of Carbon Molecular Sieves for Separation of Gas Mixtures Methane recovery from gaseous mixtures has both economical and ecological aspect. Methane from different waste gases like mine gases, nitrogenated natural gases and biogases can be treated as the local source for production electric and heat energy. And also occurs the problem of atmosphere pollution with CH4 that shows over 20 times more harmful environmental effect in comparison with CO2. One of the ways of utilisation such gases is enrichment in methane in the PSA process, which requires appropriate adsorbents. Carbon molecular sieves (CMSs) produced in industrial and laboratory scale were selected in terms of their application to the process of methane recovery: i) from mixtures CH4/N2 - in the process controlled by adsorption equilibrium; ii) from CH4/CO2 in the process controlled by kinetic of sorption. Additionally CMSs were used for separation N2 and O2 in the air mixure. For the first group of CMSs porous structures from isotherms of sorption of N2 at 77 K were calculated. Also isotherms of sorption of methane and nitrogen at elevated pressure and ambient temperature were measured. In the result the separation coefficient was calculated. Dependence of that coefficient on the microporous structure of adsorbents was discussed. For the second CMSs group investigation of isotherms and kinetics of CH4 and CO2 sorption were carried out. In the case of carbon molecular sieves separation process is controlled by two main factors stronger adsorption and faster diffusion of CO2. Separation abilities of the CMSs were checked in test apparatus in dynamic conditions. Methane concentration was measured in outflow gas during the step of constant pressure, cocurrent flow. Gas with 95% content of methane was obtained. Time in which concentration of methane in outlet rapidly decreases can be used as the parameter which differentiates adsorbents usability for separation processes.

4

Adsorbenty węglowe - surowce, otrzymywanie, zastosowanie

Buczek B., Czepirski L.

Gospodarka Surowcami Mineralnymi

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2001

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T. 17, z. 2

29-61

PL

Omówiono metody otrzymywania, właściwości oraz główne kierunki badań nad porowatymi matariałami węglowymi (węgiel aktywny, węglowe sita cząsteczkowe, aktywne włókniny węglowe). Wykazano przydatność adsorbentów w procesach ochrony atmosfery i wód, rozdzielania mieszanin gazowych, magazynowania paliw gazowych.

EN

Carbonaceous adsorbents are higly porous materials containing mostly of carbon and exhibiting a large internal surface, and which due, to their surface properties, adsorb organic and inorganic substances from gaseous or the liquid phase. This group of adsorbents contains: active carbons, carbon molecular sieves, activated carbon fibres. The methods for production of carbonaceous adsorbents are discussed. They can, essentially, be made from all carbon - containing presursors by so-called activation process. The ability to vary the type of activation (gas activation or chemical activation) permits production of a wide range of products having adsorption properties most suited for the intended application. Main objects of research and development in this area described. The examples of typical applications of carbonaceous adsorbents (solvents recovery, air deodorization) is given. Development of new processes (pressure swing adsorption for gas separation and natural gas storage) is presented. By improved adsorption properties of carbonaceous adsorbents it became possible to come up to the reqirements for increased throughput and efficiency of processes. The future prospects for carbonaceous adsorbents call increasing sophistication in the production, of the tailored products as well as to model and design complete adsorber systems based on improved understanding of the basic adsorption process.